Rapidly solidified materials are formed by cooling materials so rapidly the kinetic processes responsible for the structure and/or phase distributions associated with prior art commercially produced materials are suppressed. The structure of rapidly solidified materials may be amorphous, microcrystalline or a combination thereof. Because of the fine structure and the suppressed phase transformations, many rapidly solidified materials have improved magnetic, electric, mechanical and/or corrosion properties when compared to materials of the same chemistry produced using conventional prior art techniques.
The demand for rapidly solidified materials has grown as their unique properties are identified and components are designed to utilize these properties. Because of the improvement in electrical and magnetic properties, motors, generators and transformers smaller in size, yet having equivalent or better performance than their conventional counter parts can be made through the appropriate utilization of components made from, or coated with, rapidly solidified materials. Because of increased corrosion resistance, parts with sharp edges, and which are more resistant to corrosive environments, can be formed and made from rapidly solidified materials or materials coated with rapidly solidified powders.
Although the applications for amorphous and microcrystalline materials have grown significantly in the past decade, the methods of manufacturing such materials has not kept pace. Most rapidly solidified materials are made by a process such as is taught in U.S. Pat. No. 4,389,258 of Dickson et al. entitled METHOD FOR HOMOGENIZING THE STRUCTURE OF RAPIDLY SOLIDIFIED MICROCRYSTALLINE METAL POWDERS. The '258 patent teaches a process whereby molten metal is jet cast onto a chill surface. FIG. 3 of the '258 patent shows a jet caster which includes a quartz crucible with a bottom nozzle. An alloy is melted in the quartz crucible and pressure forces a stream of the molten metal through the nozzle onto the periphery of a rotating chilled wheel.
U.S. Pat. No. 993,904 of Edward Halford Strange, entitled APPARATUS FOR MAKING METAL STRIPS, FOIL, SHEETS OR RIBBONS teaches a device for maintaining a constant level of molten metal in a vessel which is located in close proximity to a moving cylinder. The vessel is provided with an overflow having a length equal to the width of the strip, sheet or ribbon which is to be produced. Metal overflows from the vessel onto a rotating cylinder.
The present invention is directed to a spill chill process for producing rapidly solidified materials. Using the equipment and method of the present invention, materials with widely varying chemistries, melting temperatures and reactivity can be rapidly solidified. Furthermore, the present equipment and method increases the efficiency and reliability with which rapidly solidified materials can be produced.
Using the present invention, rapidly solidified materials can be produced from feed materials having different melting points, different thermal conductivities and different electrical properties.
The present technique produces the rapidly solidified amorphous materials and does so through the unique creative application of an improvement on the technology taught in the 1911, '904 patent.